Identifying and Selectively Controlling Reverse-Noise Contribution on a Per-Access-Terminal Basis

1. A method comprising: an access node providing wireless service to a plurality of access terminals on a carrier in a coverage area, the carrier comprising a reverse link; the access node taking a measurement of reverse noise rise (RNR) on the carrier during at least one turn of a round-robin process that comprises the access terminals in the plurality taking turns transmitting traffic data on the reverse link; the access node determining a respective RNR contribution of at least one access terminal in the plurality wherein, for each access terminal for which the access node determines a respective RNR contribution, the access node does so using at least a baseline RNR value and the measurement of RNR taken by the access node during the at least one access terminal's respective turn in the round-robin process, wherein the baseline RNR value is a silent-interval RNR, the method further comprising at least one of (a) the access node measuring the silent-interval RNR during a silent-interval-RNR turn, wherein the round-robin process further comprises the silent-interval-RNR turn and (b) the access node measuring the silent-interval RNR at a time other than during the round-robin process; the access node using the at least one determined RNR contribution to identify a high-contributor set of one or more access terminals in the plurality; and the access node instructing the access terminals in the high-contributor set to reduce their respective reverse-link-traffic transmission power level.

2. The method of claim 1 , wherein the plurality of access terminals is a subset of a larger group of access terminals to which the access node is providing wireless service on the carrier in the coverage area.

3. The method of claim 2 , wherein the subset consists of those access terminals in the larger group that are at least one of (a) operating according to IS-856, Release 0, (b) operating according to IS-856, Revision A, (c) operating according to a particular communications protocol, and (d) roaming.

4. The method of claim 2 , wherein the subset is a first subset, wherein the first subset consists of those access terminals in the larger group that have a wireless-service account with a particular wireless-service provider that operates the access node, the method further comprising: the access node also providing wireless service to a second subset of access terminals on the carrier in the coverage area, the second subset of access terminals consisting of those access terminals on the carrier that do not have a wireless-service account with the particular wireless-service provider that operates the access node; and the access node instructing the access terminals in the second subset to reduce their respective reverse-link-traffic transmission power level.

5. The method of claim 1 , wherein the round-robin process comprises the access terminals in the plurality taking turns according to at least one of (a) MAC IDs respectively associated with the access terminals in the plurality, (b) Walsh codes respectively associated with the access terminals in the plurality, and (c) round-robin sequence numbers assigned respectively by the access node.

6. The method of claim 1 , wherein the access terminals in the plurality taking turns transmitting traffic data on the reverse link comprises the access terminals in the plurality taking turns as the only access terminal transmitting traffic data on the reverse link.

7. The method of claim 1 , wherein the round-robin process comprises at least one access terminal taking more than one turn.

8. The method of claim 7 , wherein determining the respective RNR contribution of a given access terminal in the plurality is based on the measurements of RNR taken during each of the given access terminal's turns during the round-robin process.

9. The method of claim 1 , wherein determining the RNR contribution of the at least one access terminal in the plurality further comprises determining the RNR contribution of all access terminals in the plurality.

10. The method of claim 1 , wherein the high-contributor set consists of those access terminals, among the access terminals in the plurality, having an RNR contribution that is greater than a threshold portion of a coverage-area-wide RNR.

11. The method of claim 1 , wherein the high-contributor set consists of those access terminals, among the access terminals in the plurality, having an RNR contribution that is greater than a threshold multiple of an average of all determined RNR contributions.

12. The method of claim 1 , wherein the high-contributor set consists of a given set of a pre-determined number of access terminals each having, among the access terminals in the plurality, a respective RNR contribution that is comparatively higher than that of any access terminal that is in the plurality but that is not in the given set.

13. The method of claim 1 , wherein instructing the access terminals in the high-contributor set to reduce their respective reverse-link-traffic transmission power level comprises transmitting a set reverse activity bit (RAB) to the access terminals in the high-contributor set.

14. The method of claim 1 , wherein the access node instructing the access terminals in the high-contributor set to reduce their respective reverse-link-traffic transmission power level is conditioned on the access node determining that a coverage-area-wide RNR exceeds a coverage-area-wide-RNR threshold.

15. The method of claim 14 , wherein the access node (i) determining an RNR contribution of at least one access terminal in the plurality and (ii) using the at least one determined RNR contribution to identify the high-contributor set are also conditioned on the access node determining that the coverage-area-wide RNR exceeds the coverage-area-wide-RNR threshold.

16. The method of claim 15 , wherein the access node taking a measurement of RNR on the carrier during at least one turn of the round-robin process is also conditioned on the access node determining that the coverage-area-wide RNR exceeds the coverage-area-wide-RNR threshold.

17. An access node comprising: a communication interface comprising a wireless-communication interface; a processor; and data storage containing program instructions executable by the processor for causing the access node to carry out functions including: providing wireless service to a plurality of access terminals on a carrier in a coverage area, the carrier comprising a reverse link; taking a measurement of reverse noise rise (RNR) on the carrier during at least one turn of a round-robin process that comprises the access terminals in the plurality taking turns transmitting traffic data on the reverse link; determining a respective RNR contribution of at least one access terminal in the plurality wherein, for each access terminal for which the access node determines a respective RNR contribution, the access node does so using at least a baseline RNR value and the measurement of RNR taken by the access node during the at least one access terminal's respective turn in the round-robin process, wherein the baseline RNR value is a silent-interval RNR, the method further comprising at least one of (a) the access node measuring the silent-interval RNR during a silent-interval-RNR turn, wherein the round-robin process further comprises the silent-interval-RNR turn and (b) the access node measuring the silent-interval RNR at a time other than during the round-robin process; using the at least one determined RNR contribution to identify a high-contributor set of one or more access terminals in the plurality; and instructing the access terminals in the high-contributor set to reduce their respective reverse-link-traffic transmission power level.

18. The access node of claim 17 , wherein the plurality of access terminals is a subset of a larger group of access terminals to which the access node is providing wireless service on the carrier in the coverage area.

19. The access node of claim 18 , wherein the subset is a first subset, wherein the first subset consists of those access terminals in the larger group that have a wireless-service account with a particular wireless-service provider that operates the access node, the method further comprising: the access node also providing wireless service to a second subset of access terminals on the carrier in the coverage area, the second subset of access terminals consisting of those access terminals on the carrier that do not have a wireless-service account with the particular wireless-service provider that operates the access node; and the access node instructing the access terminals in the second subset to reduce their respective reverse-link-traffic transmission power level.

20. The access node of claim 17 , wherein the round-robin process comprises the access terminals in the plurality taking turns according to at least one of (a) MAC IDs respectively associated with the access terminals in the plurality, (b) Walsh codes respectively associated with the access terminals in the plurality, and (c) round-robin sequence numbers assigned respectively by the access node.

21. The access node of claim 17 , wherein the access terminals in the plurality taking turns transmitting traffic data on the reverse link comprises the access terminals in the plurality taking turns as the only access terminal transmitting traffic data on the reverse link.

22. The access node of claim 17 , wherein determining the RNR contribution of the at least one access terminal in the plurality further comprises determining the RNR contribution of all access terminals in the plurality.

23. The access node of claim 17 , wherein the high-contributor set consists of those access terminals, among the access terminals in the plurality, having an RNR contribution that is greater than a threshold portion of a coverage-area-wide RNR.

24. The access node of claim 17 , wherein the high-contributor set consists of those access terminals, among the access terminals in the plurality, having an RNR contribution that is greater than a threshold multiple of an average of all determined RNR contributions.

25. The access node of claim 17 , wherein the high-contributor set consists of a given set of a pre-determined number of access terminals each having, among the access terminals in the plurality, a respective RNR contribution that is comparatively higher than that of any access terminal that is in the plurality but that is not in the given set.